Vaporizer, various devices using the same, and vaporizing method

ABSTRACT

There is provided a vaporizer that can be used for a long period of time without being clogged and can supply a raw material stably to a reaction section. The evaporator includes a dispersion section  8  having a gas passage  2  formed in a dispersion section body  1,  a gas introduction port  4  for introducing a pressurized carrier gas  3  into the gas passage  2,  means  6  for supplying a raw material solution  5  to the gas carrier passing through the gas passage  2,  a gas outlet  7  for sending the carrier gas containing the dispersed raw material solution  5  to a vaporization section  22,  and means  18  for cooling the gas passage  2;  and the vaporization section  22  for heating and vaporizing the carrier gas in which the raw material solution is dispersed, having a vaporization tube  20  connected to the reaction section of an apparatus and the gas outlet  7  of the dispersion section  8,  and a heater  21  for heating the vaporization tube  20,  and is characterized in that the pressure of the reaction section is set lower than the pressure of the vaporization tube.

TECHNICAL FIELD

The present invention relates to a vaporizer suitably used for a filmforming apparatus such as a MOCVD film forming apparatus and avaporizing method, and a CVD thin film forming apparatus and othervarious types of apparatuses.

BACKGROUND ART

A problem arising in the development of DRAM is a decrease in storagecapacitance caused by miniaturization. From the viewpoint of softwareerror, capacitance of the same level as that of the old generation isrequired, so that it is necessary to take some measures. As themeasures, although the cell structure up to 1M has been a planarstructure, from 4M, a three-dimensional structure called a stackstructure or a trench structure has been adopted to increase thecapacitor area. Also, for the dielectric film, which has conventionallybeen a thermally-oxidized film of substrate Si, a film formed bylaminating a thermally-oxidized film and a CVD nitrided film on poly Si(this laminated film is generally called an ON film) has been adopted.For 16M DRAM, in order to further increase the area contributing to thecapacitance, for the stack type, a three-dimensional type in which theside surface is used, a fin type in which the back surface of plate isused, and the like type have been used.

In such a three-dimensional structure, however, there arises a problemin that the number of processes increases due to the complication ofprocess and the yield decreases due to the increase in heightdifference. For this reason, it is said that it is difficult to realizeDRAM of 256M bits or higher capacitance. Therefore, as one means forfurther increasing the degree of integration without changing thepresent structure of DRAM, there has been devised a method in which thedielectric of capacitance is changed over to one having a largedielectric constant. As a dielectric thin film having a large dielectricconstant, attention was first paid to a thin film of a large dielectricconstant single metal paraelectric oxide such as Ta₂O₅, Y₂O₃, and HfO₂.The specific dielectric constant of Ta₂O₅ is 28, that of Y₂O₃ is 16,that of HfO₂ is about 24, which are four to seven times that of SiO₂.

However, in application to DRAM of 256M or higher, a three-dimensionalcapacitor structure is needed. As a material which has a far largerspecific dielectric constant than that of these oxides and is expectedto be applied to DRAM, three kinds of (Ba_(x)Sr_(1-x))TiO₃,Pb(Zr_(y)Ti_(1-y))O₃, and (Pb_(a)L_(1-a)) (Zr_(b)Ti_(1-b))O₃ have beenregarded as very likely. A Bi-based laminar structure having acrystalline structure highly similar to that of a superconductivematerial has recently received great attention because it has a largedielectric constant and self polarization of ferroelectriccharacteristic, and hence it is superior as a nonvolatile memory.

Generally, SrBi₂TaO₉ ferroelectic thin film is formed by the MOCVD(metal organic chemical vapor deposition) method which is practical andpromising.

The raw materials for the ferroelectic thin film are, for example, threekinds of organic metal complexes of Sr(DPM)₂, Bi(C₆H₅)₃, and Ta(OC₃H₅)₅.Each of these materials is used as a raw material solution by beingdissolved in THF (tetrahydrofuran), hexane, or other solvents.Sr(Ta(OEt)6)₂ and Bi(OtAm)₃ are also used as a raw material solution bybeing dissolved in hexane or other solvents. DPM is the abbreviation ofdipivaloylmethane.

The material properties of these raw materials are given in Table 1.TABLE 1 Properties of raw material for ferroelectric thin film Boilingpoint (° C.)/ pressure (mmHg) Melting point (° C.) Sr(DPM)₂ 213/0.1 210Bi(C₆H₅)₃ 130/0.1 80 Ta(OC₂H₅)₅ 118/0.1 22 THF 67 −109 Sr(Ta(OEt)₅)₂176/0.1 130 Bi(OtAm)₃  87/0.1 90

An apparatus used for the MOCVD method includes a reaction section inwhich the SrBi₂TaO₉ thin film raw material undergoes gas phase reactionand surface reaction to form a film and a supply section in which theSrBi₂TaO₉ thin film raw material and an oxidizing agent are supplied tothe reaction section.

The supply section is provided with a vaporizer for vaporizing the thinfilm raw material.

Conventionally, as a technique concerning the vaporizer, methods shownin FIG. 16 has been known. The method shown in FIG. 16(a), which iscalled a metal filter method, is a method in which vaporization isaccomplished by introducing a raw material solution heated to apredetermined temperature to a metal filter used for increasing thecontact area of gas existing in the surroundings with the SrBi₂TaO₉ferroelectric thin film raw material solution.

However, in this technique, the metal filter is clogged by vaporizationfor several hours, which poses a problem in that this metal filtercannot be used for a long period of time. The inventor presumed that thereason for this is that the solution is heated and a substance having alower vaporization temperature evaporates.

FIG. 16(b) shows a technique in which a raw material solution isdischarged through a minute hole of 10 μm by applying a pressure of 30kgf/cm² to the raw material solution, by which the raw material solutionis vaporized by expansion.

However, in this technique, the minute hole is clogged by vaporizationfor several hours, which poses a problem in that this minute hole cannotbe used for a long period of time.

Also, in the case where the raw material solution is a mixed solution ofa plurality of organic metal complexes, for example, a mixed solution ofSr(DPM)₂/THF and Bi(C₆H₅)₃/THF and Ta(OC₃H₅)₅/THF, and vaporization isaccomplished by the heating of this mixed solution, a solvent having thehighest vapor pressure (in this case, THF) vaporizes earliest, whichposes a problem in that the raw material cannot be supplied stablybecause the organic metal complexes deposit on the heated surface. Inall methods shown in FIG. 1, the quantity of heat capable of evaporatingor changing the solvent is added in a liquid or mist state.

Furthermore, in the MOCVD, in order to obtain a film with highhomogeneity, it is requested to obtain vaporized gas in which the rawmaterial solution disperses homogeneously. However, the above-describedconventional techniques do not necessarily meet the request.

To meet the above-described request, the inventor has separatelyprovided a technique described below.

Specifically, as shown in FIG. 15, there has been provided a vaporizerfor MOCVD including:

(1) a dispersion section having a gas passage formed in the interior, agas introduction port for introducing a pressurized carrier gas to thegas passage, means for supplying a raw material solution to the gaspassage, a gas outlet for sending the carrier gas containing the rawmaterial solution to a vaporization section, means for cooling the gaspassage, and a radiation heat preventive blowoff portion cooled so thatthermal energy is not applied to the raw material gas in the dispersionsection by radiation heat from the vaporization section; and

(2) a vaporization section for heating and vaporizing the carrier gascontaining the raw material solution sent from the dispersion section,having a vaporization tube one end of which is connected to a reactiontube of an MOCVD apparatus and the other end of which is connected tothe gas outlet, and heating means for heating the vaporization tube; anda radiation heat preventive blowoff portion cooled so that thermalenergy is not applied to the raw material gas in the dispersion sectionby radiation heat from the vaporization section.

This technique provides a vaporizer for MOCVD that is clogged far lessthan the conventional example so that it can be used for a long periodof time, and can supply a raw material stably to the reaction section.

Also, in this technique, an introduction port of oxygen heatedbeforehand is provided on the downstream side of the vaporizationsection.

However, in this technique as well, deposition of crystals is found inthe gas passage, so that clogging still occurs in some cases.

Also, a large quantity of carbon (30 to 40 at %) is contained in theformed film. In order to remove this carbon, annealing (for example,800° C., 60 minutes, oxygen atmosphere) must be performed at a hightemperature after film formation.

Furthermore, in the case where film formation is accomplished, thereoccur large variations in percentage composition.

An object of the present invention is to provide a vaporizer which canrestrain the occurrence of air bubbles and can be expected to restrainvariations in thin film deposit rate caused by the air bubbles, and avaporizing method.

DISCLOSURE OF THE INVENTION

The present invention provides a vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the atomized raw material solution, which is sent from thedispersion section, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

the pressure of the reaction section is set lower than the pressure ofthe vaporization tube.

The film forming apparatus is preferably a normal-pressure CVD apparatusin which the pressure of the reaction section is controlled to 900 to760 Torr.

The film forming apparatus is preferably a depressurized CVD apparatusin which the pressure of the reaction section is controlled to 20 to 0.1Torr.

The film forming apparatus is preferably a low-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 0.1 to 0.001Torr.

The present invention provides a vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from the dispersionsection, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

(3) the dispersion section has a dispersion section body having acylindrical or conical hollow portion and a rod having an outsidediameter smaller than the inside diameter of the cylindrical or conicalhollow portion,

the rod has one or two or more spiral grooves on the vaporizer side atthe outer periphery of the rod, and is inserted in the cylindrical orconical hollow portion, the inside diameter thereof sometimes spreadingin a taper shape toward the vaporizer side, and

the pressure of the reaction section is set lower than the pressure ofthe vaporization tube.

The film forming apparatus is preferably a normal-pressure CVD apparatusin which the pressure of the reaction section is controlled to 900 to760 Torr.

The film forming apparatus is preferably a depressurized CVD apparatusin which the pressure of the reaction section is controlled to 20 to 0.1Torr.

The film forming apparatus is preferably a low-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 0.1 to 0.001Torr.

The present invention provides a vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from the dispersionsection, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

an oxidizing gas can be added to the carrier gas from the gasintroduction port or an oxidizing gas can be introduced from a primaryoxygen supply port, and

the pressure of the reaction section is set lower than the pressure ofthe vaporization tube.

The film forming apparatus is preferably a normal-pressure CVD apparatusin which the pressure of the reaction section is controlled to 900 to760 Torr.

The film forming apparatus is preferably a depressurized CVD apparatusin which the pressure of the reaction section is controlled to 20 to 0.1Torr.

The film forming apparatus is preferably a low-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 0.1 to 0.001Torr.

The present invention provides a vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from the dispersionsection, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

a radiation preventive portion having a minute hole is provided on theoutside of the gas outlet,

the carrier gas and an oxidizing gas can be introduced from the gasintroduction port, and

the pressure of the reaction section is set lower than the pressure ofthe vaporization tube.

The film forming apparatus is preferably a normal-pressure CVD apparatusin which the pressure of the reaction section is controlled to 900 to760 Torr.

The film forming apparatus is preferably a depressurized CVD apparatusin which the pressure of the reaction section is controlled to 20 to 0.1Torr.

The film forming apparatus is preferably a low-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 0.1 to 0.001Torr.

The present invention provides a vaporizer including:

a disperser formed with

a plurality of solution passages for supplying a plurality of rawmaterial solutions,

a mixing section for mixing the raw material solutions supplied from thesolution passages,

a supply passage one end of which communicates with the mixing sectionand which has an outlet on the vaporization section side,

a gas passage arranged so that a carrier gas or a mixed gas of thecarrier gas and oxygen is blown to the mixed raw material solutioncoming from the mixing section in the supply passage, and

cooling means for cooling the supply passage; and

a vaporization section for heating and vaporizing the carrier gascontaining the raw material solutions, which is sent from the disperser,having

a vaporization tube one end of which is connected to a reaction sectionof a film forming apparatus or other various types of apparatuses andthe other end of which is connected to the outlet of the disperser, and

heating means for heating the vaporization tube, characterized in that

a radiation preventive portion having a minute hole is provided on theoutside of the outlet,

a primary oxygen supply port capable of introducing an oxidizing gas isprovided just near the dispersion blowoff portion, and

the pressure of the reaction section is set lower than the pressure ofthe vaporization tube.

The film forming apparatus is preferably a normal-pressure CVD apparatusin which the pressure of the reaction section is controlled to 900 to760 Torr.

The film forming apparatus is preferably a depressurized CVD apparatusin which the pressure of the reaction section is controlled to 20 to 0.1Torr.

The film forming apparatus is preferably a low-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 0.1 to 0.001Torr.

The present invention provides a film forming apparatus including thevaporizer as described above.

The present invention provides a vaporizing method in which a rawmaterial solution is introduced into a gas passage, and a carrier gas issprayed toward the introduced raw material solution, by which the rawmaterial solution is sheared and atomized into raw material mist, andthen, the raw material mist is supplied to a vaporization section to bevaporized, characterized in that

control is carried out so that the pressures of the carrier gas and theintroduced raw material solution are almost equal in a region in whichthe carrier gas comes into contact with the introduced raw materialsolution.

The present invention provides a vaporizing method in which a rawmaterial solution is introduced into a gas passage, and a carrier gas issprayed toward the introduced raw material solution, by which the rawmaterial solution is sheared and atomized into raw material mist, andthen, the raw material mist is supplied to a vaporization section to bevaporized, characterized in that

control is carried out so that the pressure of the carrier gas is lowerthan the pressure of the introduced raw material solution in a region inwhich the carrier gas comes into contact with the introduced rawmaterial solution.

Control is preferably carried out so that the pressure of the carriergas is lower than the pressure of the introduced raw material solutionby 760 Torr at a maximum in a region in which the carrier gas comes intocontact with the introduced raw material solution.

Control is preferably carried out so that the pressure of the carriergas is lower than the pressure of the introduced raw material solutionby 100 to 10 Torr at a maximum in a region in which the carrier gascomes into contact with the introduced raw material solution.

The present invention provides a vaporizing method in which a rawmaterial solution is introduced into a gas passage, and a carrier gas issprayed toward the introduced raw material solution, by which the rawmaterial solution is sheared and atomized into raw material mist, andthen, the raw material mist is supplied to a vaporization section to bevaporized, characterized in that

control is carried out so that the pressures of the carrier gas and theraw material solution are higher than the vapor pressure of theintroduced raw material solution in a region in which the carrier gascomes into contact with the introduced raw material solution.

In a vaporizing method in which a raw material solution is introducedinto a gas passage, and a carrier gas is sprayed toward the introducedraw material solution, by which the raw material solution is sheared andatomized into raw material mist, and then, the raw material mist issupplied to a vaporization section to be vaporized,

control is preferably carried out so that the pressures of the carriergas and the raw material solution are 1.5 times or more higher than thevapor pressure of the introduced raw material solution in a region inwhich the carrier gas comes into contact with the introduced rawmaterial solution.

Oxygen is preferably contained in the carrier gas in advance.

The present invention provides a film characterized by being formedafter vaporization is accomplished by the vaporizing method as describedabove.

The present invention provides an electronic device including theabove-described film.

The present invention provides a CVD thin film forming methodcharacterized in that after a pressurizing gas dissolved in a transfersolution using the pressurizing gas has been removed, the flow rate iscontrolled, and the vaporizer is connected to a CVD apparatus to form athin film.

It is preferable that the transfer solution using the pressurizing gasbe caused to flow in a fluororesin pipe in which transmission speed iscontrolled, whereby only the pressurizing gas be removed.

It is preferable that when only the pressurizing gas is removed bycausing the transfer solution using the pressurizing gas to flow in afluororesin pipe etc. in which transmission speed is controlled, theremoval of the pressuring gas be accelerated by controlling the externalenvironment of the fluororesin pipe etc.

The present invention provides a vaporizing method in which a rawmaterial solution is introduced into a passage and introduced into adepressurized and heated vaporizer, and is sprayed or dripped into thevaporizer, whereby the raw material solution is atomized and vaporized,characterized in that control is carried out so that the pressure of theraw material solution in the tip end portion of the passage is higherthan the vapor pressure of the introduced raw material solution.

Control is preferably carried out so that the pressure of the rawmaterial solution is 1.5 times or more the vapor pressure of theintroduced raw material solution in the tip end portion of the passage.

The present invention provides a vaporizing method in which a rawmaterial solution and a carrier gas are introduced into a depressurizedand heated vaporizer, and are sprayed into the vaporizer, whereby theraw material solution is atomized and vaporized, characterized in thatcontrol is carried out so that the pressure of the raw material solutionin the tip end portion of the passage is higher than the vapor pressureof the introduced raw material solution.

Control is preferably carried out so that the pressure of the rawmaterial solution is 1.5 times or more the vapor pressure of the rawmaterial solution in the tip end portion of the passage.

Oxygen is preferably contained in the carrier gas in advance.

Control is preferably carried out so that the pressures of the carriergas and the introduced raw material solution are almost equal in aregion in which the carrier gas comes into contact with the introducedraw material solution.

Control is preferably carried out so that the pressure of the carriergas is lower than the pressure of the introduced raw material solutionin a region in which the carrier gas comes into contact with theintroduced raw material solution.

Control is preferably carried out so that the pressure of the carriergas is lower than the pressure of the introduced raw material solutionby 760 Torr at a maximum in a region in which the carrier gas comes intocontact with the introduced raw material solution.

Control is preferably carried out so that the pressure of the carriergas is lower than the pressure of the introduced raw material solutionby 100 to 10 Torr at a maximum in a region in which the carrier gascomes into contact with the introduced raw material solution.

Control is preferably carried out so that the pressures of the carriergas and the raw material solution are higher than the vapor pressure ofthe introduced raw material solution in a region in which the carriergas comes into contact with the introduced raw material solution.

Control is preferably carried out so that the pressures of the carriergas and the raw material solution are 1.5 times or more higher than thevapor pressure of the introduced raw material solution in a region inwhich the carrier gas comes into contact with the introduced rawmaterial solution.

The present invention provides a CVD thin film forming apparatus inwhich a transfer solution using a pressurizing gas is introduced intothe vaporizer via a mass-flow controller, and the vaporizer is connectedto the CVD apparatus, whereby a thin film is formed, characterized inthat degassing means for removing a pressuring gas is provided on theupstream side of the mass-flow controller.

Also, the present invention is applicable to the following vaporizersand vaporizing methods:

A vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the atomized raw material solution, which is sent from thedispersion section, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

a radiation preventive portion having a minute hole is provided on theoutside of the gas outlet.

A vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage, and

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from the dispersionsection, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

(3) the dispersion section has a dispersion section body having acylindrical or conical hollow portion and a rod having an outsidediameter smaller than the inside diameter of the cylindrical or conicalhollow portion,

the rod has one or two or more spiral grooves on the vaporizer side atthe outer periphery of the rod, and is inserted in the cylindrical orconical hollow portion, and

(4) a cooled radiation preventive portion is provided which has a minutehole on the gas outlet side on the outside of the gas outlet and theinside diameter of which spreads in a taper shape toward the vaporizer.

A vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the atomized raw material solution, which is sent from thedispersion section, having

a vaporization tube one end of which is connected to a reaction sectionof film forming apparatus or other various types of apparatuses and theother end of which is connected to the gas outlet, and

heating means for heating the vaporization tube, characterized in that

a small quantity of oxidizing gas can be added to the carrier gas suchas Ar, N₂ or helium from the gas introduction port or an oxidizing gasor the mixed gas thereof can be introduced from a primary oxygen supplyport just near a blowoff portion.

A vaporizer including:

(1) a dispersion section having

a gas passage formed in the interior,

a gas introduction port for introducing a carrier gas into the gaspassage,

means for supplying a raw material solution to the gas passage,

a gas outlet for sending the carrier gas containing the raw materialsolution to a vaporization section, and

means for cooling the gas passage; and

(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from the dispersionsection, characterized in that

a radiation preventive portion having a minute hole is provided on theoutside of the gas outlet, and

the carrier gas and an oxidizing gas can be introduced from the gasintroduction port.

A vaporizing method in which a raw material solution is introduced intoa gas passage, and a carrier gas with a high velocity is sprayed towardthe introduced raw material solution, by which the raw material solutionis sheared and atomized into raw material gas, and then, the rawmaterial gas is supplied to a vaporization section to be vaporized,characterized in that oxygen is contained in the carrier gas in advance.

A vaporizing method using a vaporizer formed with

a plurality of solution passages for supplying raw material solutions,

a mixing section for mixing the raw material solutions supplied from thesolution passages,

a supply passage one end of which communicates with the mixing sectionand which has an outlet on the vaporization section side,

a gas passage arranged so that a carrier gas or a mixed gas of thecarrier gas and oxygen is blown to the mixed raw material solutioncoming from the mixing section in the supply passage, and

cooling means for cooling the supply passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a principal portion of a vaporizerfor MOCVD in accordance with example 1;

FIG. 2 is a general sectional view of a vaporizer for MOCVD inaccordance with example 1;

FIG. 3 is a system diagram of MOCVD;

FIG. 4 is a front view of a reserve tank;

FIG. 5 is a sectional view showing a principal portion of a vaporizerfor MOCVD in accordance with example 2;

FIG. 6 is a sectional view showing a principal portion of a vaporizerfor MOCVD in accordance with example 3;

FIGS. 7(a) and 7(b) are sectional views showing modifications of a gaspassage of a vaporizer for MOCVD in accordance with example 4;

FIG. 8 is a sectional view showing a principal portion of a vaporizerfor MOCVD in accordance with example 5;

FIG. 9 is a view of a rod used for the vaporizer for MOCVD in accordancewith example 5, FIG. 9(a) being a side view, FIG. 9(b) being a sectionalview taken along the line X-X, and FIG. 9(c) being a sectional viewtaken along the line Y-Y;

FIG. 10 is a side view showing a modification of FIG. 9(a);

FIG. 11 is a graph showing an experimental result in example 6;

FIG. 12 is a side sectional view showing example 8;

FIG. 13 is a schematic diagram showing a gas supply system of example 8;

FIG. 14 is a side sectional view showing example 9;

FIG. 15 is a sectional view showing the latest conventional technique;

FIGS. 16(a) and 16(b) are sectional views of a conventional vaporizerfor MOCVD;

FIG. 17 is a graph showing a crystallization characteristic of an SBTthin film;

FIG. 18 is a graph showing a polarization characteristic of acrystallized SBT thin film;

FIG. 19 is a detailed view of a vaporizer;

FIG. 20 is a general view of a vaporizer;

FIG. 21 is a view showing an example of an SBT thin film CVD apparatususing a vaporizer;

FIG. 22 is a sectional view showing an example of a film formingapparatus;

FIG. 23 is a view showing a construction for heating medium circulationshown in FIG. 22;

FIG. 24 is a view of a degassing system;

FIG. 25 is a view showing an example of degassing method;

FIG. 26 is a view showing an example of degassing method;

FIG. 27 is a graph showing dependency of air bubble occurrence onresidence time and pressure;

FIG. 28 is a view of an air bubble evaluation vaporizer;

FIG. 29 is a view showing behavior of air bubbles; and

FIG. 30 is a view showing various types of vaporizers.

EXPLANATION OF REFERENCE NUMERALS

FIG. 2

-   a: FILM FORMING APPARATUS-   b: COOLING WATER    FIG. 3-   a: RECOVERY SECTION-   b: REACTION SECTION-   c: SUPPLY SECTION-   d: EXHAUST GAS-   e: VAPORIZER-   f: MASS-FLOW CONTROLLER-   g: OXYGEN-   h: HEATED SECTION    FIG. 4-   a: RAW MATERIAL SOLUTION-   b: ARGON    FIG. 7-   a: GAS PASSAGE    FIG. 12-   a: MOCVD APPARATUS-   b: COOLING WATER    FIG. 13-   a: RECOVERY SECTION-   b: REACTION SECTION-   c: SUPPLY SECTION-   d: EXHAUST GAS-   e: VAPORIZER-   f: MASS-FLOW CONTROLLER-   g: OXYGEN-   h: HEATED SECTION    FIG. 16-   a: METAL FILTER    FIG. 19-   a: FIRST CARRIER-   b: RAW MATERIAL SOURCE INTRODUCING ORIFICE-   c: COOLING WATER-   d: SECOND MIXING SECTION & ATOMIZING NOZZLE PORTION-   e: SECOND CARRER-   f: FIRST MIXING SECTION    FIG. 20-   a: SHEATH HEATER-   b: PERMA-   c: HEAT EXCHANGER-   d: VAPORIZATION SECTION PROPER DISTANCE AND TEMPERATURE-   e: MANTLE HEATER-   f: VAPORIZATION HEAD-   g: CONTROLLER-   h: PRESSURE GAGE-   i: VAPORIZATION SECTION AUTOMATIC PRESSURE REGULATING VALVE-   j: THERMOCOUPLE-   k: O₂ OR AIR (SWITCHING OVER)-   l: INTRODUCED GAS (SWIRL MIXING)-   m: HORIZONTAL SECTIONAL VIEW (GAS FLOW IMAGE)-   n: THERMOCOUPLE-   o: SHOWER HEAD-   p: HOT WALL CHAMBER    FIG. 21-   a: DEGASSING SYSTEM-   b: N₂, Ar OR He-   c: HEAT EXCHANGER-   d: SUBSTRATE (4″ TO 8″)-   e: LOAD LOCK CHAMBER-   f: WAFER CONVEYING MECHANISM-   g: LOADER-   h: GATE VALVE-   i: EXHAUST GAS-   j: VAPORIZER-   k: PROCESS CHAMBER    FIG. 24-   a: PRESSURIZED GAS-   b: PRESSURE GAGE-   c: CONTAINER HEXANE (5 LITERS)-   d: DEGASSING METHOD (A, B, C, D, E)-   e: LIQUID MASS-FLOW CONTROLLER-   f: OCCURRENCE OF AIR BUBBLES WAS CHECKED AT OUTLET OF LIQUID    MASS-FLOW CONTROLLER-   g: GLASS CONTAINER-   h: PUMP-   i: EXHAUST GAS    FIG. 25-   A: PFA TUBE BEING HELD IN AIR (LENGTH OF ⅛″ PFA TUBE WAS CHANGED)-   a: LENGTH: 15 TO 120 cm-   B: USE OF DEPRESSURIZING SYSTEM OF OWN MAKING (⅛″ PFA TUBE WAS USED)-   b: LENGTH: 120 cm-   c: LENGTH IN DEPRESSURIZING SYSTEM: 200 cm, 800 cm-   d: PRESSURE IN SYSTEM: 0.1 Torr    FIG. 26-   C: POLYIMIDE TUBE BEING HELD IN AIR-   a: LENGTH: 131 cm-   D: USE OF DEPRESSURIZING SYSTEM OF OWN MAKING (POLYIMIDE TUBE WAS    USED)-   b: LENGTH: 131 cm-   c: LENGTH IN DEPRESSURIZING SYSTEM: 140 cm-   d: PRESSURE IN SYSTEM: 0.1 Torr-   E: COMMERCIALLY AVAILABLE DEGASSING SYSTEM (MANUFACTURED BY YOKOHAMA    RIKA Co., Ltd.)-   e: ⅛″ O.D. PFA TUBE 120 cm-   f: DEGASSING SYSTEM-   g: DEPRESSURIZATION: MAKER SPECIFICATION (FOR LIQUID CHROMATOGRAPHY)    FIG. 27-   a: LINE OUTLET PRESSURE (Torr)-   b: REGIDENCE TIME (min)-   c: AIR BUBBLE NON-OCCURRENCE REGION-   d: AIR BUBBLE OCCURRENCE REGION-   e: LOWER LIMIT PRESSURE AT WHICH AIR BUBBLES WERE NOT CONFIRMED-   f: UPPER LIMIT PRESSURE AT WHICH AIR BUBBLES WERE CONFIRMED-   g: ⅛″ PFA TUBE BEING USED (O.D. 3.2 mm, I.D. 1.32 mm)    FIG. 28-   a: FIRST CARRIER-   b: SECOND CARRIER    FIG. 29-   a: EVAPORATION HEAD    FIG. 30-   a: PERMEATION TYPE-   b: CARRIER-   c: HEATER-   d: LIQUID-   e: DRIP TYPE-   f: PRESSURIZED SEEPAGE TYPE-   g: DIAPHRAGM TYPE-   h: PRESSURIZED BLOWOFF TYPE-   1 dispersion section body-   2 gas passage-   3 carrier gas-   4 gas introduction port-   5 raw material solution-   6 raw material supply hole-   7 gas outlet-   8 dispersion section-   9 a, 9 b, 9 c, 9 d machine screw-   10 rod-   18 means for cooling (cooling water)-   20 vaporization tube-   22-   21 heating means (heater)-   23 vaporization section-   24 connecting portion-   25 joint oxygen introducing means (primary oxygen (oxidizing gas)    supply port)-   29 raw material supply inlet-   30 a, 30 b, 30 c, 30 dmass-flow controller-   31 a, 31 b, 31 c, 31 dvalve-   32 a, 32 b, 32 c, 32 dreserve tank-   33 carrier gas bomb-   42 exhaust outlet-   40 valve-   44 reaction tube-   46 gas pack-   51 taper-   70 groove-   101 minute hole-   102 radiation preventive portion-   107 OUTLET-   109 MIXING SECTION-   110 SUPPLY PASSAGE-   120 GAS PASSAGE-   150 DISPERSER-   200 oxygen introducing means (secondary oxygen (oxidizing carrier    supply port)-   301 upstream ring-   302 downstream ring-   303 a, 303 b heat transfer path-   304 heat conversion plate-   304 a gas vent hole gas nozzle-   306 exhaust outlet-   308 orifice-   312 substrate heater-   320 heating medium inlet-   321 heating medium outlet-   390 heat input medium-   391 heat output medium-   3100 silicon substrate

BEST MODE FOR CARRYING OUT THE INVENTION EXAMPLE 1

FIG. 1 shows a vaporizer for MOCVD in accordance example 1.

In this example, the vaporizer includes:

a dispersion section 8 having a gas passage 2 formed in a dispersionsection body 1 forming a dispersion section,

a gas introduction port 4 for introducing a pressurized carrier gas 3 tothe gas passage 2,

means (raw material supply hole) 6 for supplying a raw material solution5 to the carrier gas passing through the gas passage 2 and for makingthe raw material solution 5 in a mist form,

a gas outlet 7 for sending the carrier gas (raw material gas) containingthe mist-form raw material solution 5 to a vaporization section 22, and

means (cooling water) 18 for cooling the carrier gas flowing in the gaspassage 2; and

the vaporization section 22 for heating and vaporizing the carrier gasin which the raw material solution is dispersed, which is sent from thedispersion section 8, having

a vaporization tube 20 one end of which is connected to a reaction tubeof an MOCVD apparatus and the other end of which is connected to the gasoutlet 7 of the dispersion section 8, and

heating means (heater) 21 for heating the vaporization tube 20, and

a radiation preventive portion 102 having a minute hole 101 is providedon the outside of the gas outlet 7.

Next, this example is explained in more detail.

In the example shown in FIG. 1, the interior of the dispersion sectionbody 1 is a cylindrical hollow portion. A rod 10 is inserted in thehollow portion, and the gas passage 2 is formed by the internal wall ofthe dispersion section body and the rod 10. The hollow portion is notlimited to the cylindrical shape, and may take any other shapes. Forexample, a conical shape is preferable. The conical angle of the conicalhollow portion is preferably 0 to 45°, more preferably 8 to 20°. Thesame is true in other examples.

The cross sectional area of the gas passage is preferably 0.10 to 0.5mm². If it is less than 0.10 mm², the fabrication is difficult to do. Ifit exceeds 0.5 mm², it is necessary to use a high-pressure carrier gaswith a high flow rate to speed up the carrier gas.

If the carrier gas with a high flow rate is used, a high-capacity largevacuum pump is needed to keep a reaction chamber in a depressurizedstate (for example, 1.0 Torr). Since it is difficult to use a vacuumpump having an evacuation capacity exceeding 10,000 liters/min (at 1.0Torr), in order to achieve industrially practical application, a properflow rate, i.e., a gas passage area of 0.10 to 0.5 mm² is preferable.

At one end of this gas passage 2, the gas introduction port 4 isprovided. The gas introduction port 4 is connected with a carrier gas(for example, N₂, Ar, He) source (not shown).

At the side of a substantially central portion of the dispersion sectionbody 1, the raw material supply hole 6 is provided so as to communicatewith the gas passage 2, so that the raw material solution 5 isintroduced into the gas passage 2, and thus the raw material solution 5can be dispersed in the carrier gas passing through the gas passage 2 toform the raw material gas.

At one end of the gas passage 2, the gas outlet 7 communicating with thevaporization tube 20 of the vaporization section 22 is provided.

In the dispersion section body 1, a space 11 for causing the coolingwater 18 to flow is formed. By causing the cooling water 8 to flow inthis space, the carrier gas flowing in the gas passage 2 is cooled.Alternatively, in place of this space, a Peltier element etc. may beprovided to cool the carrier gas. Since the interior of the gas passage2 of the dispersion section 8 is thermally affected by the heater 21 ofthe vaporization section 22, a solvent and an organic metal complex ofthe raw material solution do not vaporize at the same time in the gaspassage 2, and only the solvent vaporizes. Therefore, by cooling thecarrier gas in which the raw material solution is dispersed, flowing inthe gas passage 2, vaporization of only the solvent is prevented. Inparticular, the cooling on the downstream side of the raw materialsupply hole 6 is important, and therefore at least a portion on thedownstream side of the raw material supply hole 6 is cooled. The coolingtemperature is a temperature equal to or lower than the boiling point ofsolvent. For example, in the case of THF, the cooling temperature is 67°C. or lower. In particular, the temperature at the gas outlet 7 isimportant.

In this example, the radiation preventive portion 102 having the minutehole 101 is further provided on the outside of the gas outlet7.Reference numerals 103 and 104 denote sealing members such as O-rings.This radiation preventive portion 102 can be formed of Teflon(registered trade name), stainless steel, ceramics, or the like. Also,the radiation preventive portion 102 is preferably formed of a materialhaving high thermal conductivity.

According to the knowledge of the inventor, in the conventionaltechnique, the heat in the vaporization section overheats the gas in thegas passage 2 via the gas outlet 7 as radiation heat. Therefore, even ifthe gas is cooled by the cooling water 18, a low melting point componentin the gas deposits near the gas outlet 7.

The radiation preventive portion is a member for preventing theradiation heat from propagating to the gas. Therefore, thecross-sectional area of the minute hole 101 is preferably smaller thanthe cross-sectional area of the gas passage 2. It is preferably equal toor less than ½, more preferably equal to or less than ⅓ of thecross-sectional area of the gas passage 2. Also, the minute hole ispreferably miniaturized. In particular, it is preferably miniaturized toa size such that the flow velocity of emitting gas is subsonic.

Also, the length of the minute hole is preferably equal to or more thanfive times, more preferably equal to or more than ten times the minutehole size.

Also, by cooling the dispersion section, blockage due to carbide in thegas passage (especially the gas outlet) is prevented even if thevaporizer is used for a long period of time.

On the downstream side of the dispersion section body 1, the dispersionsection body 1 is connected to the vaporization tube 20. The connectionbetween the dispersion section body 1 and the vaporization tube 20 ismade by a joint 24, and this portion serves as a connecting portion 23.

FIG. 2 is a general view. The vaporization section 22 includes thevaporization tube 20 and the heating means (heater) 21. The heater 21 isa heater for heating and vaporizing the carrier gas in which the rawmaterial solution is dispersed, flowing in the vaporization tube 20. Theheater 21 has conventionally been formed by affixing a cylindricalheater or a mantle heater at the outer periphery of the vaporizationtube 20. However, in order to heat the vaporization tube 20 so that auniform temperature is achieved in the lengthwise direction of thevaporization tube, a method in which a liquid or a gas having high heatcapacity is used as a heating medium is most excellent. Therefore, thismethod was used in this example.

As the vaporization tube 20, stainless steel, for example, SUS316L ispreferably used. The dimensions of the vaporization tube 20 may bedetermined appropriately so that its length is enough to heat thevaporized gas. For example, when a SrBi₂Ta₂O₉ raw material solution of0.04 ccm is vaporized, the vaporization tube 20 having an outsidediameter of ¾ inches and a length of several hundred millimeters can beused.

The downstream side end of the vaporization tube 20 is connected to areaction tube of an MOCVD apparatus. In this example, an oxygen supplyport 25 is provided on the vaporization tube 20 as oxygen supply meansso that oxygen heated to a predetermined temperature can be fed to thecarrier gas.

First, the supply of raw material solution to the vaporizer isdescribed.

As shown in FIG. 3, reserve tanks 32 a, 32 b, 32 c and 32 dare connectedto the raw material supply hole 6 via mass-flow controllers 30 a, 30 b,30 cand 30 dand valves 31a, 31 b, 31 c and 31 d, respectively.

Also, the reserve tanks 32 a, 32 b, 32 c and 32 dare connected with acarrier gas bomb 33.

The details of the reserve tank are shown in FIG. 4.

The reserve tank is filled with the raw material solution. The carriergas (for example, inert gas Ar, He, Ne) of, for example, 1.0 to 3.0kgf/cm² is sent into each of the reserve tank (content volume: 300 cc,made of SUS). Since the interior of the reserve tank is pressurized bythe carrier gas, the raw material solution is pushed up in the tube onthe side contacting with the solution, and is sent under pressure to theliquid mass-flow controller (manufactured by STEC, full-scale flow rate:0.2 cc/min), where the flow rate is controlled. The raw materialsolution is conveyed to the raw material supply hole 6 through a rawmaterial supply inlet 29 of the vaporizer.

The raw material solution, whose flow rate has been controlled to afixed value by the mass-flow controller, is conveyed to a reactionsection by the carrier gas. At the same time, oxygen (oxidizing agent),whose flow rate has been controlled to a fixed value by a mass-flowcontroller (manufactured by STEC, full-scale flow rate: 2 L/min), isalso conveyed to the reaction section.

Since in the raw material solution, a liquid-form or solid-form organicmetal complex is dissolved in THF and other solvents at ordinarytemperature, if it is left as it is, the organic metal complex isdeposited by the evaporation of THF solvent, and it finally becomes in asolid form. Therefore, it is assumed that the tube in contact with theraw liquid may be blocked by the deposited organic metal complex. Inorder to restrain the blockage of tube, a cleaning line is providedconsidering that the interior of the tube and vaporizer should becleaned with THF and other solvents after the film forming work has beenfinished. In the cleaning operation, a portion fitting to each workincluding raw material container replacement work in a section from thecontainer outlet side to the vaporizer is washed off with the solvent.

The valves 31 b, 31 c and 31 dwere opened, and the carrier gas was sentunder pressure into the reserve tanks 32 b, 32 c and 32 d. The rawmaterial solution is sent under pressure to the mass-flow controller(manufactured by STEC, full-scale flow rate: 0.2 cc/min), where the flowrate is controlled. The raw material solution is conveyed to the rawmaterial supply hole 6 of the vaporizer.

On the other hand, the carrier gas was introduced through the gasintroduction port of the vaporizer. The maximum pressure on the supplyport side is preferably equal to or lower than 3 kgf/cm². At this time,the maximum flow rate of gas capable of passing through is about 1200cc/min, and the flow velocity in the gas passage 2 reaches one hundredand several tens meters per second.

When the raw material solution is introduced through the raw materialsupply hole 6 to the carrier gas flowing in the gas passage 2 of thevaporizer, the raw material solution is sheared by the high-velocityflow of carrier gas and changed to ultrafine particles. As a result, theraw material solution is dispersed in the carrier gas in an untrafineparticle state. The carrier gas in which the raw material solution isdispersed in an untrafine particle state (raw material gas) is atomizedas being in a high-velocity state by the vaporization section 22 and isreleased. The angle formed between the gas passage and the raw materialsupply hole is optimized. In the case where the angle between thecarrier flow path and the raw material solution introduction port is anacute angle (30 degrees), the solution is drawn by the gas. If the angleis equal to or larger than 90 degrees, the solution is pushed by thegas. The optimum angle is determined from the viscosity and flow rate ofsolution. When the viscosity or the flow rate is high, the solution iscaused to flow smoothly by making the angle more acute. In the casewhere hexane is used as the solvent to form an SBT film, an angle ofabout 84 degrees is preferable because both viscosity and flow rate arelow.

Three kinds of raw material solutions, whose flow rate has beencontrolled to a fixed value, flow into the gas passage 2 through the rawmaterial supply hole 6 via the raw material supply inlet 29, and aftermoving in the gas passage together with the carrier gas, which forms ahigh-velocity gas flow, they are released to the vaporization section22. In the dispersion section 8 as well, the raw material solution isheated by the heat from the vaporization section 22, and the evaporationof THF and other solvents is accelerated. Therefore, a section from theraw material supply inlet 29 to the raw material supply hole 6 and asection of the gas passage 2 are cooled by water or other cooling media.

The vaporization of the raw material solution, which is dispersed in thecarrier gas in a fine particle form, released from the dispersionsection 8 is accelerated during the conveyance in the vaporization tube20 heated to a predetermined temperature by the heater 21. By thefeeding of oxygen heated to a predetermined temperature from the oxygensupply port 25 provided just before the raw material solution reachesthe reaction tube of MOCVD, a mixed gas is formed, and flows into thereaction tube. In this example, evaluation was carried out by analyzingthe reaction mode of vaporized gas in place of film formation.

A vacuum pump (not shown) was connected from an exhaust outlet 42 toremove water and other impurities in the reaction tube 44 by means of anevacuating operation for about 20 minutes, and a valve 40 on thedownstream side of the exhaust outlet 42 was closed.

Cooling water was caused to flow in the vaporizer at a flow rate ofabout 400 cc/min. On the other hand, a carrier gas of 3 kgf/cm² wascaused to flow at a flow rate of 495 cc/min. After the reaction tube 44was sufficiently filled with the carrier gas, the valve 40 was opened.The temperature at the gas outlet 7 was lower than 67° C.

The interior of the vaporization tube 20 was heated to 200° C., asection from the reaction tube 44 to a gas pack 46 and the gas pack wereheated to 100° C., and the interior of the reaction tube 44 was heatedto 300° C. to 600° C.

The interior of the reserve tank was pressurized by the carrier gas, anda predetermined liquid was caused to flow by the mass-flow controller.

Sr(DPM)₂, Bi(C₆H₅)₃, Ta(OC₂H₅)₅, and THF were caused to flow at flowrates of 0.04 cc/min, 0.08 cc/min, 0.08 cc/min, and 0.2 cc/min,respectively.

After 20 minutes, a valve just in front of the gas pack 46 was opened torecover a reaction product in the gas pack 46. The reaction product wasanalyzed with a gas chromatograph, and it was examined whether thedetected product coincides with the product in the reaction formulastudied based on the reaction theory. As a result, in this example, thedetected product coincided well with the product in the reaction formulastudied based on the reaction theory.

Also, the amount of carbides adhering to the external surface on the gasoutlet 7 side of the dispersion section body 1 was measured. As theresult, the amount of adhering carbides was very small, and was furthersmaller than in the case where the apparatus shown in FIG. 14 was used.

In the case of a raw material solution in which a metal to be used as afilm raw material is mixed with or dissolved in a solvent, the rawmaterial solution is generally such that the metal is a complex and in aliquid/liquid state (perfect solvent solution). However, as the resultof a careful examination of raw material solution conducted by theinventor, there was gained a knowledge that the metal complex is notnecessarily in a scattered molecular state, and the metal complex itselfis present as fine particles with a size of 1 to 100 nm in the solventin some cases or is partially present as a solid/liquid state. It isconsidered that the clogging at the time of vaporization is liable tooccur especially when the raw material solution is in such a state. Whenthe evaporator in accordance with the present invention is used,clogging does not occur even when the raw material solution is in such astate.

Also, in a solution in which the raw material solution is present, thefine particles are liable to settle at the bottom by means of thegravity thereof. Therefore, to prevent clogging, it is preferable thatconvection be caused in the solution by heating the bottom portion (to atemperature equal to or lower than the evaporating temperature ofsolvent) to homogeneously disperse the fine particles. Also, it ispreferable that not only the bottom portion be heated but also the sideface of the container upper surface be cooled. Needless to say, theheating is performed at a temperature equal to or lower than theevaporating temperature of solvent.

It is preferable that a heater set or control the quantity of heat forheating the evaporation tube upper region so as to be larger than thequantity of heat for heating the downstream region. Specifically, sincewater-cooled gas blows off from the dispersion section, it is preferablethat there be provided a heater that sets or controls the quantity ofheat for heating so as to be large in the evaporation tube upper regionand be small in the downstream region.

EXAMPLE 2

FIG. 5 shows a vaporizer for MOCVD in accordance with example 2.

In this example, a cooling water passage 106 was formed at the outerperiphery of the radiation preventive portion 102, and cooling means 50was provided at the outer periphery of the connecting portion 23 to coolthe radiation preventive portion 102.

Also, a concave portion 107 was provided around the outlet of the minutehole 101.

Other points are the same as in example 1.

In this example, the detected product coincided better with the productin the reaction formula studied based on the reaction theory than in thecase of example 1.

Also, the amount of carbides adhering to the external surface on the gasoutlet 7 side of the dispersion section body 1 was measured, with theresult that the amount of adhering carbides was about ⅓ of the case ofexample 1.

EXAMPLE 3

FIG. 6 shows a vaporizer for MOCVD in accordance with example 3.

In this example, the radiation preventive portion 102 has a taper 51.This taper 51 eliminates a dead zone in this portion, so that theretention of raw material can be prevented.

Other points are the same as in example 2.

In this example, the detected product coincided better with the productin the reaction formula studied based on the reaction theory than in thecase of example 2.

Also, the amount of carbides adhering to the external surface on the gasoutlet side 7 of the dispersion section body 1 was measured, with theresult that the amount of adhering carbides was nearly zero.

EXAMPLE 4

FIG. 7 shows modified examples of the gas passage.

In FIG. 7(a), grooves 70 are formed in the surface of the rod 10, andthe outside diameter of the rod 10 is almost the same as the insidediameter of the hole formed in the dispersion section body 1. Therefore,merely by inserting the rod 10 in the hole, the rod can be arranged inthe hole without eccentricity. Also, machine screws etc. need not beused. The grooves 70 serve as gas passages.

The grooves may be formed in plural numbers in parallel with the axis inthe lengthwise direction of the rod 10, or they may be formed in aspiral form in the surface of the rod 10. In the case of the spiralform, a raw material gas having high homogeneity can be obtained.

FIG. 7(b) shows an example in which mixing portions are provided in thetip end portion of the rod 10. The largest diameter in the tip endportion is almost the same as the inside diameter of the hole formed inthe dispersion section body 1. Spaces formed by the rod tip end portionand the internal surface of hole serve as gas passages.

The examples shown in FIGS. 7(a) and 7(b) are examples in which thesurface of the rod 10 is machined. However, it is a matter of coursethat a rod having a circular cross section is used, and concave portionsare formed in the surface of hole to provide gas passages. It ispreferable that the rod be arranged in accordance with H7×h6−JS7specified in JIS.

EXAMPLE 5

Example 5 is explained with reference to FIG. 8.

The vaporizer for MOCVD of this example includes:

a dispersion section 8 having

a gas passage formed inside,

a gas introduction port 4 for introducing a pressurized carrier gas 3into the gas passage,

means for supplying raw material solutions 5 a and 5 b to the gaspassage, and a gas outlet 7 for sending the carrier gas containing theraw material solutions 5 a and 5 b to a vaporization section 22; and

the vaporization section 22 for heating and vaporizing the carrier gasin which the raw material solutions are contained, which is sent fromthe dispersion section 8, having

a vaporization tube 20 one end of which is connected to a reaction tubeof an MOCVD apparatus and the other end of which is connected to the gasoutlet 7 of the dispersion section 8, and

heating means for heating the vaporization tube 20, and

the dispersion section 8 has a dispersion body 1 having a cylindricalhollow portion and a rod 10 having an outside diameter smaller than theinside diameter of the cylindrical hollow portion;

one or two or more spiral grooves 60 are formed on the vaporizer side atthe outer periphery of the rod 10;

the rod 10 is inserted in the cylindrical hollow portion; and

a radiation preventive portion 101 is provided which has a minute hole101 on the outside of the gas outlet 7 and the inside diameter of whichspreads in a taper shape toward the vaporizer 22.

When the raw material solution 5 is supplied to the gas passage throughwhich the high-velocity carrier gas 3 flows, the raw material solutionis sheared and atomized. Specifically, the raw material solution, whichis a liquid, is sheared by a high-velocity flow of carrier gas, and madeparticles. The raw material solution having been made particles isdispersed in the carrier gas in a particulate state. This point is thesame as in example 1.

In order to accomplish the shearing and atomization in the optimummanner, the following conditions are favorable.

The raw material solution 5 is supplied preferably at 0.005 to 2 cc/min,more preferably at 0.005 to 0.02 cc/min, and still more preferably at0.1 to 0.3 cc/min. When a plurality of raw material solutions (includingsolvent) are supplied at the same time, the total quantity thereofshould preferably be as described above.

Also, the carrier gas is supplied preferably at a rate of 10 to 200m/sec, more preferably at a rate of 100 to 200 m/sec.

There is a mutual relation between the flow rate of raw materialsolution and the flow rate of carrier gas. It is a matter of course toselect a cross-sectional area and a shape of flow path that realizes theoptimum shearing and atomization and can obtain ultrafine particle mist.

In this example, the spiral groove 60 is formed at the outer peripheryof the rod 10, and a gap space is present between the dispersion sectionbody 1 and the rod 10. Therefore, the carrier gas containing theatomized raw material solution goes straight in this gap space as astraight flow, and also forms a swirl flow along the spiral groove 60.

The inventor found that the atomized raw material solution is disperseduniformly in the carrier gas in the state in which the straight flow andthe swirl flow coexist. The reason why uniform dispersion can beobtained if the straight flow and the swirl flow coexist is notnecessarily clear. However, the following reason is possible. Theexistence of swirl flow produces a centrifugal force in the flow, and asecondary flow is produced. This secondary flow accelerates the mixtureof the raw material with the carrier gas. That is, it is considered thatthe secondary derived flow is produced in the direction perpendicular tothe flow by the centrifugal effect of swirl flow, and thereby theatomized raw material solution is dispersed uniformly in the carriergas.

Next, this example is explained in more detail.

In this example, the configuration is such that as one example, fourkinds of raw material solutions 5 a, 5 b , 5 c and 5 d (5 a, 5 b and 5 care organic metal raw materials and 5 d is a solvent raw material suchas THF) are supplied to the gas passage.

In order to mix the carrier gas containing the raw material solutionshaving been atomized and made in an ultrafine particle shape (referredto as a “raw material gas”), in this example, a portion in which thespiral groove is absent is provided on a downstream side of a portioncorresponding to a raw material supply hole 6 of the rod 10. Thisportion serves as a premixing portion 65. In the premixing portion 65,the raw material gas of three kinds of organic metals is mixed to someextent, and further a perfectly mixed raw material gas is formed in theregion of the downstream spiral structure. In order to obtain auniformly mixed raw material gas, the length of the mixing portion 65 ispreferably 5 to 20 mm, more preferably 8 to 15 mm. If the length thereofis out of the above range, only on kind of mixed raw material gas with ahigh concentration of the raw material gases of three kinds of organicmetals is sometimes sent to the vaporization section 22.

In this example, an end portion 66 on the upstream side of the rod 10 isprovided with a parallel portion 67 and a taper portion 58. In thecylindrical hollow portion of the dispersion section body 1 as well, aparallel portion having an inside diameter equal to the outside diameterof the parallel portion 67 of the rod 10, which corresponds to theparallel portion 67, and a taper portion with the same taper as thetaper of the rod 10, which corresponds to the taper portion 58, areprovided. Therefore, when the rod 10 is inserted from the left-hand sidein the figure, the rod 10 is held in the hollow portion of thedispersion section body 1.

In this example, unlike the case of example 1, since the rod 10 is heldwith the taper being provided, even if a carrier gas having a pressurehigher than 3 kgf/cm² is used, the rod 10 can be prevented from moving.Specifically, if the holding technique shown in FIG. 8 is employed, thecarrier gas can be caused to flow at a pressure equal to or higher than3 kgf/cm². As a result, the cross-sectional area of gas passage isdecreased, and a higher-velocity carrier gas can be supplied by a smallquantity of gas. Specifically, a carrier gas with a high velocity of 50to 300 mm/s can be supplied. The same is true if this holding techniqueis employed in the above-described other examples.

As shown in FIG. 9(b), in a portion corresponding to the raw materialsupply hole 6 of the rod 10, grooves 67 a, 67 b, 67 c and 67 d areformed as carrier gas passages. The depth of each of the grooves 67 a,67 b, 67 c and 67 d is preferably 0.005 to 0.1 mm. If the depth thereofis shallower than 0.005 mm, the machining of groove is difficult. Also,the depth thereof is more preferably 0.01 to 0.05 mm. The depth in thisrange prevents the occurrence of clogging etc. Also, it can easilyprovide a high-velocity flow.

For the holding of the rod 10 and the formation of gas passage, theconstruction shown in FIG. 1 in example 1 or other constructions may beused.

The number of the spiral grooves 60 may be one as shown in FIG. 9(a), ormay be any plural numbers as shown in FIG. 10. Also, when the pluralityof spiral grooves are formed, they may be crossed. When the spiralgrooves 60 are crossed, a raw material gas dispersed more uniformly canbe obtained. However, the cross-sectional area should be such that a gasflow velocity equal to or higher than 10 m/sec can be obtained in eachgroove.

The size and shape of the spiral groove 60 is not subject to any specialrestriction. The size and shape shown in FIG. 9(c) is one example.

In this example, as shown in FIG. 8, the gas passage is cooled bycooling water 18.

Also, in this example, an expansion section 69 is independently providedin front of the inlet of the dispersion section 22, and the lengthwiseradiation preventive portion 102 is arranged in this expansion section69.

The minute hole 101 is formed on the gas outlet 7 side of the radiationpreventive portion, and the inside diameter of the minute hole 101spreads in a taper shape toward the vaporizer side.

The expansion section 69 also serves to prevent the retention of rawmaterial gas, which has been described in example 3. Needless to say,there is no need for independently provide the expansion section 69. Theintegrated construction as shown in FIG. 6 may also be used.

The expansion angle θ of the expansion section 69 is preferably 5 to 10degrees. When the expansion angle θ is within this range, the rawmaterial gas can be supplied to the dispersion section withoutdestroying the swirl flow. Also, when the expansion angle θ is withinthis range, the fluid resistance due to expansion becomes a minimum andalso the presence of dead zone becomes a minimum, so that the presenceof eddy current due to the presence of dead zone can be made a minimum.The expansion angle θ is more preferably 6 to 7 degrees. In the case ofthe example shown in FIG. 6 as well, the preferable range of θ is thesame.

EXAMPLE 6

The apparatus shown in FIG. 8 was used, and the raw material solutionsand the carrier gas were supplied under the following conditions, bywhich the homogeneity of raw material gas was investigated.

Quantity of Introduced Raw Material Solutions: Sr(DPM) 20.04 cc/mmBi(C₆H₅) 30.08 cc/mm Ta(OC₂H₅)₅ 0.08 cc/mm THE 0.2 cc/mm Carrier gas:nitrogen gas 10 to 350 m/s

As a vaporizing apparatus, the apparatus shown in FIG. 8 was used. As arod, the rod shown in FIG. 9, which is not formed with the spiralgroove, was used.

The raw material solutions were supplied from the raw material supplyhole 6, and the carrier gas was supplied by changing the velocitythereof variously. From the raw material supply hole, Sr(DPM) ₂ wassupplied to the groove 67 a, Bi(C₆H₅)₃ was supplied to the groove 67 b,Ta(OC₂H₅)₅ was supplied to the groove 67 c, and THF and other solventswere supplied to the groove 67 d.

Heating was not performed in the vaporization section, and the rawmaterial gas was sampled at the gas outlet 7 to measure the particlediameter of raw material solution in the sampled raw material gas.

The measurement result is shown in FIG. 11 as a relative value (the casewhere the apparatus of the conventional example shown in FIG. 12(a) istaken as 1). As seen from FIG. 11, by rendering the flow velocity equalto or higher than 50 m/s, the dispersed particle diameter decreases, andby rendering the flow velocity equal to or higher than 100 m/s, thedispersed particle diameter further decreases. However, when the flowvelocity is rendered equal to or higher than 200 m/s, the dispersedparticle diameter saturates. Therefore, the preferred range is 100 to200 m/s.

EXAMPLE 7

In example 7, a rod formed with a spiral groove was used.

Other points are the same as in example 6.

In example 6, in an extended portion of the groove, the concentration ofraw material solution supplied to the groove was high. Specifically, inan extended portion of the groove 67 a, the concentration of Sr(DPM)₂was high, in an extended portion of the groove 67 b, the concentrationof Bi(C₆H₅)₃ was high, and in an extended portion of the groove 67 b,the concentration of Ta(OC₂H₅)₅ was high.

However, in this example, for the mixed raw material gas obtained at theend of spiral groove, each organic metal raw material was uniform in anyportions.

EXAMPLE 8

Example 8 is shown in FIGS. 12 and 13.

Conventionally, oxygen has been introduced only on the downstream sideof the vaporization section 22 as shown in FIG. 2. As described in thesection of conventional technique, a large quantity of carbon iscontained in the film formed by the conventional technique. Also, thecomposition in the raw material and the composition in the formed filmhave been different from each other. Specifically, when vaporization andfilm formation are accomplished by adjusting the raw material to thestoichiometric composition, the actually formed film has a compositiondifferent from the stoichiometric composition. In particular, aphenomenon such that bismuth is scarcely contained (about 0.1 at %) hasbeen observed.

The inventor found that the cause for this relates to the introductionposition of oxygen. Specifically, it was found that if as shown in FIG.20, if oxygen is introduced, together with the carrier gas, from a gasintroduction port 4, a secondary oxygen supply port 200 just near ablowoff port, and a oxygen introduction port (primary oxygen supplyport) 25, the difference between the composition in the formed film andthe composition in the raw material solution can be made extremelysmall.

It is optional to mix oxygen with the carrier gas in advance and tointroduce this mixed gas through the gas introduction port 4.

EXAMPLE 9

By using the vaporizer shown in FIGS. 19 and 20 and the CVD apparatusshown in FIG. 21, an SBT film was formed, and further polarizationcharacteristics etc. were evaluated.

Concretely, the conditions of vaporizer and reaction chamber werecontrolled as described below, and an SBT film was formed on a substrateobtained by forming platinum of 200 nm on an oxidized silicon substrate.

Concrete Conditions:

-   Hexaethoxystrontiumtantalum Sr[Ta(OC₂H₅)₆]₂ 0.1 mol solution    (solvent: hexane) 0.02 ml/min-   Tri-t-amyloxide bismuth Bi(O-t-C₅H₁₁)₃ 0.2 mol solution (solvent:    hexane) 0.02 ml/min-   First carrier Ar=200 sccm (introduced through a gas introduction    port 4)-   First carrier O₂=10 sccm (introduced through a gas introduction port    4)-   Second carrier Ar=20 sccm (introduced through a gas introduction    port 200)-   O₂=10 sccm (introduced through a gas introduction port 200)-   Reaction oxygen O₂=200 sccm (introduced from a dispersion blowoff    portion lower portion 25)

Reaction oxygen temperature 216° C. (temperature is controlled by aheater provided separately before reaction oxygen is introduced from adispersion blowoff portion lower portion) Wafer temperature 475° C.Space temperature 299° C. Space distance  30  mm Shower head temperature201° C. Reaction pressure  1  Torr Film forming time  20  minutesResults:

SBT film thickness about 300 nm (deposition speed about 150 nm/min) SBTcomposition Sr  5.4 at % Bi 16.4 at % Ta 13.1 at % O 61.4 at % C  3.5 at%

The difference between the composition in the formed film and thecomposition in the raw material solution was very small, and thedeposition speed was about five times the conventional speed. It isfound that the effect of introducing small amount of oxygen through thegas introduction port 4 together with the carrier gas is extremelygreat. The carbon content is as low as 3.5 at %.

Because the temperature of the reaction oxygen (200 cc/min) wasprecisely controlled (to 216° C.) by the separately provided heaterbefore the reaction oxygen was introduced from the dispersion blowoffportion lower portion 25, from the fact that contamination of the lowerpart of evaporation tube was eliminated, it was verified that the effectof restraining the re-condensation/sublimation(solidification) ofvaporized organic metal compound is great.

After the SBT thin film has been formed, crystallization treatment wasperformed at 750° C. for 30 minutes in an oxygen atmosphere, andmeasurement and evaluation were carried out by forming an upperelectrode. As a result, high crystallization characteristics andpolarization characteristics were exhibited. These results are shown inFIGS. 17 and 18.

If an oxidizing gas such as oxygen is merely introduced through the gasintroduction port 4 or a primary oxygen supply port just near a blowoffport, it is preferable that, as shown in FIG. 2, oxygen be introduced atthe same time on the downstream side of a vaporization section and thequantity of oxygen be controlled appropriately, because by doing this,the difference in composition is decreased and the carbon content isalso decreased.

The content of carbon in the formed film can be decreased to 5 to 20% ofthe conventional example.

An example of an SBT thin film deposition process is explained withreference to FIG. 20.

A valve 2 is opened, and a valve 1 is closed, by which a reactionchamber is evacuated to a high vacuum. After several minutes, a wafer istransferred from a load lock chamber to a reaction chamber.

At this time, in a vaporizer,

-   hexaethoxystrontiumtantalum (Sr[Ta(OC₂H₅)₆]₂ 0.1 mol solution    (solvent: hexane) 0.02 ml/min),-   tri-t-amyloxide bismuth (Bi(O-t-C₅H₁₁)₃ 0.2 mol solution (solvent:    hexane) 0.02 ml/min),-   first carrier Ar (=200 sccm (introduced through a gas introduction    port 4)), and-   first carrier O₂ (=10 sccm (introduced through a gas introduction    port 4))-   flow and are drawn to a vacuum pump through the valve 2 and an    automatic pressure regulating valve.

At this time, the pressure gage is controlled to 4 Torr by the automaticpressure regulating valve.

When the temperature becomes stable several minutes after the wafer hasbeen transferred, the valve 1 is opened, and the valve 2 is closed, bywhich the following gas is caused to flow into the reaction chamber tostart deposition.

-   Hexaethoxystrontiumtantalum Sr[Ta(OC₂H₅)₆]₂ 0.1 mol solution    (solvent: hexane) 0.02 ml/min-   Tri-t-Amyloxide bismuth Bi(O-t-C₅H₁₁)₃ 0.2 mol solution (solvent:    hexane) 0.02 ml/min-   First carrier Ar=200 sccm (introduced through the gas introduction    port 4)-   First carrier O₂=10 sccm (introduced through the gas introduction    port 4)-   Second carrier Ar=20 sccm (introduced through the gas introduction    port 200)-   O₂=10 sccm (introduced through the gas introduction port 200)-   Reaction oxygen O₂=200 sccm (introduced from the dispersion blowoff    portion lower portion 25)-   Reaction oxygen temperature 216° C. (temperature is controlled by    the heater provided separately before reaction oxygen is introduced    from the dispersion blowoff portion lower portion)-   Wafer temperature 475° C.

The reaction pressure chamber pressure is controlled to 1 Torr (by a notdescribed automatic pressure regulating valve).

After predetermined time (20 minutes, in this example) has elapsed, thevalve 2 is opened, and the valve 1 is closed, by which the deposition isfinished.

The reaction chamber is evacuated to a high vacuum to remove thereaction gas completely, and after one minute, the wafer is taken out tothe load lock chamber.

Capacitor Structure

-   Pt(200 nm)/CVDSBT(300 nm)/Pt(175 nm)/Ti(30 nm)/SiO₂/Si    Capacitor Forming Process-   Lower electrode formation Pt(175 nm)/TI(30 nm) CVDSBT film formation    (300 nm)-   SBT film crystallization treatment (diffusion furnace annealing:    wafer 750° C., 30 min, O₂ atmosphere)-   Upper electrode formation Pt(200 nm)-   Annealing: 650° C., 02, 30 min

Conventionally, since the reaction oxygen (for example, 200 sccm) hasbeen put in the vaporization tube in a room temperature state, theorganic metal gas has been cooled, and adhered and deposited in thevaporization tube.

When the temperature of the reaction oxygen supplied from the lowerportion of evacuation section is controlled, conventionally, a heaterhas been wound around a stainless steel tube (outside dimension: ¼ to1/16 inch, length: 10 to 100 cm) to control the temperature of externalwall of the stainless steel tube (to 219° C., for example).

It has been considered that the temperature of external wall of thestainless steel tube (219° C., for example) is equal to the temperatureof oxygen (flow rate: 200 sccm) flowing inside.

However, the measurement of oxygen temperature with a minutethermocouple revealed that the temperature rise is only about 35° C. inthis example.

Therefore, the temperature of oxygen after being heated was measureddirectly with a minute thermocouple, and the heater temperature wascontrolled, by which the oxygen temperature was controlled accurately.

Since it was not easy to raise the temperature of gas such as oxygenflowing in the tube, the heat exchange efficiency was improved byputting a filler in the heating tube, and the temperature of heatedoxygen gas was measured, by which the heater temperature was controlledproperly.

Means for such control is a heat exchanger shown in FIG. 20.

EXAMPLE 10

Example 10 is shown in FIG. 14.

In the above-described examples, gas is blown to each of the rawmaterial solutions to atomize the single raw material solution, andsubsequently, the atomized raw material solutions are mixed with eachother. This example provides an apparatus in which a plurality of rawmaterial solutions are mixed, and the mixed raw material solutions areatomized.

The evaporator of this example includes:

a disperser 150 formed with a plurality of solution passages 130 a and130 b for supplying raw material solutions 5 a and 5 b , a mixingsection 109 for mixing the raw material solutions 5 a and 5 b suppliedthrough the solution passages 130 a and 130 b, a supply passage 110 oneend of which communicates with the mixing section 109 and which has anoutlet 017 on the vaporization section 22 side, a gas passage 120arranged so that a carrier gas or a mixed gas of the carrier gas andoxygen is blown to the mixed raw material solution coming from themixing section 109 in the supply passage 110, and cooling means forcooling the interior of the supply passage 110; and

a vaporization section 22 for heating and vaporizing the gas containingthe raw material solutions, which is sent from the disperser 150, havinga vaporization tube one end of which is connected to a reaction tube ofan MOCVD apparatus and the other end of which is connected to the outlet107 of the disperser 150, and heating means 2 for heating thevaporization tube, and a radiation heat preventive material 102 having aminute hole 101 is arranged on the outside of the outlet 107.

This example is effective for the raw material solutions the reaction ofwhich does not proceed even if being mixed. Since the raw materialsolutions are atomized after being once mixed, the composition is exactas compared with the case where the raw material solutions are mixedafter being atomized. Also, means (not shown) for analyzing thecomposition of mixed raw material solution in the mixing section 109 isprovided, and the supply amounts of the raw material solutions 5 a and 5b are controlled based on the analysis result, by which more exactcomposition can be obtained.

Also, in this example, a rod (reference numeral 10 in FIG. 1) need notbe used. Therefore, the heat propagating in the rod does not heat theinterior of the supply passage 110. Further, the cross-sectional area ofthe supply passage 110 can be decreased as compared with the case wherethe raw material solutions are mixed after being atomized, and hence thecross-sectional area of the outlet 107 can be decreased, so that theinterior of the supply passage 110 is scarcely heated by radiation.Therefore, the deposition of crystals can be decreased without providingthe radiation preventive portion 102. In the case where it is desired tofurther prevent the deposition of crystals, the radiation preventiveportion 102 may be provided as shown in FIG. 14.

Although the number of minute holes is one in the above-describedexamples, it is a matter of course that number of minute holes may beplural. Also, the diameter of the minute hole is preferably equal to orsmaller than 2 mm. When a plurality of minute holes are provided, thediameter can be made far smaller.

Also, in the above-described examples, in the case where the carrierflow path and the raw material solution introduction port make an acuteangle (30 degrees), the solution is drawn by the gas. If the angle isequal to or larger than 90 degrees, the solution is pushed by the gas.Therefore, the angle is preferably 30 to 90°. Concretely, the optimumangle is determined from the viscosity and flow rate of solution. Whenthe viscosity is high or the flow rate is high, the solution is causedto flow smoothly by making the angle more acute. Therefore, inimplementation, the optimum angle corresponding to the viscosity andflow rate has only to be determined in advance by an experiment etc.

Also, in the above-described examples, it is optional to provide amechanism for controlling the distance of space between a shower headand a susceptor to an arbitrary distance.

Furthermore, it is preferable that a liquid mass-flow controller forcontrolling the flow rate of raw material solution be provided, anddegassing means for gas removal be provided on the upstream side of theliquid mass-flow controller. If degassing is not accomplished and theraw material solution is introduced to the mass-flow controller,variations in the formed films occur on the same wafer or betweenwafers. By introducing the raw material solution to the mass-flowcontroller after the removal of helium etc., the above-describedvariations in film thickness are decreased remarkably.

By providing means for controlling the temperature of raw materialsolution, helium transfer container, liquid mass-flow controller, andpipes in front of and behind the mass-flow controller to a fixedtemperature, the variations in film thickness can further be prevented.Also, the change of properties of a chemically unstable raw materialsolution can be prevented. When the SBT thin film is formed, control isprecisely carried out in the range of 5 to 20° C. The range of 12° C.±1° C. is especially preferable.

Also, in a substrate surface treatment apparatus in which apredetermined gas is blown to the substrate surface of a siliconsubstrate etc. to carry out surface treatment on the substrate surfaceas shown in FIGS. 22 and 23, it is optional to configure a heatingmedium circulation path having an upstream ring 301 connected to aheating medium inlet 320 for once-through flow of heating medium, adownstream ring 302 connected to a heating medium outlet 321 for apredetermined heating medium, and at least two heat transfer paths 303 aand 303 b which connect the upstream ring 1 and the downstream ring 2 toeach other in the parallel direction, for making the gas at apredetermined temperature by alternating the flow path direction fromthe upstream ring 1 to the downstream ring 302 between the adjacent heattransfer paths 303 a and 303 b.

Also, the substrate surface treatment apparatus preferably has a heatconversion plate 304 thermally connected to the heating mediumcirculation path in a predetermined plane in the heating mediumcirculation path and in a plane formed in the flow path of the heatingmedium in the parallel direction so that the portion in the plane of theheat conversion plate 304 can be heated to a substantially uniformtemperature by the heating medium.

Further, in the plane of the heat conversion plate 304, a plurality ofvent holes for causing the predetermined gas to pass through in thevertical direction of the plane are preferably formed so that thepredetermined gas passing through the vent hole can be heated to asubstantially uniform temperature in the plane.

Thereupon, the configuration is such that the flow path direction fromthe upstream ring to the downstream ring between the adjacent heattransfer paths of the heating medium circulation path is alternated.Therefore, the difference in temperature in a region adjacent to theheat transfer path is configured so as to be high/low/high/low. . . . Bythis configuration, the heat conversion plate can be heated or cooleduniformly. Further, a heat conversion plate thermally connected to theheating medium circulation path is provided in a plane formed in theflow path of heating medium in the parallel direction. Therefore, aportion in the plane of this heat conversion plate can be heated to asubstantially uniform temperature by the heating medium.

EXAMPLE 11

Regarding Measures Against Air Bubbles Occurring in a CVD Solution:

When the CVD solution is pressurized to 3 to 4 kg/cm² by using gas(argon, helium, etc.), and the flow rate thereof is controlled by usinga liquid mass-flow controller, the pressurizing gas dissolves in thesolvent (for example, hexane).

Just after the solution has passed through an MFC, the pressure ofsolution is decreased to 1 to 0 kg/cm² by pressure loss. Therefore, mostof dissolved pressurizing gas comes out as air bubbles.

The occurring air bubbles cause fluctuations in the flow rate ofsolution, so that it is necessary to restrain the occurrence of airbubbles.

The solubility of gas (argon, helium, etc.) in the solvent is asdescribed below according to Chemical Handbook (edited by The ChemicalSociety of Japan, revised 4th edition, published by Maruzen).

-   1: Solvent hexane (25° C.) helium solubility 2.60e-4 mol (partial    pressure 101.3 kPa)-   2: Solvent hexane (25° C.) argon solubility 25.2e-4 mol (partial    pressure 101.3 kPa)

The argon solubility of 25.2e-4 mol means that 65 cc of argon dissolvesin 1 mol (130 cc) of hexane. Since the quantity of dissolution isproportional to the gas pressure, gas of two to three times theabove-described quantity dissolves. The solubility of helium is about10% of that of argon.

Next, a method for removing (degassing) the dissolved gas is carriedout.

The pressurizing gas dissolves, and is observed as air bubbles when thesolution is depressurized. This system is shown in FIG. 24. Thedegassing method is shown in FIGS. 25 and 26. The results weresummarized in FIG. 27 and Table 2. FIG. 26 shows an air bubbleevaluating vaporizer.

It is found that when helium is used as the pressurizing gas, degassingcan be accomplished to a level at which problems scarcely arise bycausing the gas to pass through a PFA tube of 15 to 60 cm. However, whenthe pressure becomes equal to or lower than 400 Torr, air bubbles ofseveral percent are observed, so that the solution pressure cannot bedecreased to a value equal to or lower than 400 Torr.

When argon is used as the pressurizing gas, 50% or more of the interiorof pipe is occupied by the occurring air bubbles.

It was found that argon can scarcely be removed even if a PFA tubehaving high gas permeability is used. As shown in Table 2, the vaporpressure of hexane is about 120 Torr at 20° C. Therefore, it is apparentthat it is necessary to keep the pressure of hexane solution equal to orhigher than 120 Torr to restrain the occurrence of air bubbles.

The properties of solvents are given in Table 3. TABLE 2 (2) (3) (4) (5)(6) (7) 1. (1)-1 Ar 3 0.1 120 A x 50.0 740 He 3 0.1 60 A ◯ 0.0 740 He 30.1 40 A x 2.3 740 He 3 0.1 30 A x 5.5 740 He 3 0.1 20 A x 9.1 740 He 30.1 10 A x 13.8 740 He 3 0.02 15 A ◯ 0.0 740 He 3 0.02 15 A ◯ 0.0 680 He3 0.02 15 A ◯ 0.0 633 He 3 0.02 15 A ◯ 0.0 520 He 3 0.02 15 A x 507 He 30.02 15 A x 417 He 3 0.02 60 A Δ 430 He 3 0.02 60 A x 3.0 403 He 3 0.0260 A x 5.0 390 He 3 0.02 60 A x 13.0 375 He 3 0.02 120 A x 400 2. (1)-2Ar 3 0.1 120 B(PFA8m) x 50.0 740 He 3 0.1 120 B(PFA8m) ◯ 0.0 740 He 30.1 120 B(PFA2m) ◯ 0.0 740 3. (1)-3 Ar 3 0.1 131 C x 54.5 740 Ar 3 0.02131 C x 58.2 740 4. (1)-4 Ar 3 0.1 131 D x 60.1 740 Ar 3 0.02 131 D x60.6 740 5. (1)-5 Ar 1 0.1 120 E ◯ 0.0 740 Ar 2 0.1 120 E ◯ 0.0 740⁽¹⁾: Air bubble evaluation result⁽²⁾: Pressurizing gas⁽³⁾: Container pressure (kgf/cm²)⁽⁴⁾: LMFC (coM)⁽⁵⁾: Length of PFA tube (cm)⁽⁶⁾: Air bubble occurrence and air bubble percentage (%)⁽⁷⁾: Presure at line outlet (Torr)⁽⁸⁾: Container pressure is indicated by gage pressure. LFMC is anabbreviation of liquid mass-flow controller, showing values at 25° C.and 1 atm.⁽⁹⁾: Pressure at line outlet (Torr) is indicated by absolute pressure.⁽¹⁰⁾: Outside and inside diameters of each tube are as follows:PFA 1/8″ tube: O.D. 3.2 mm, I.D. 1.32 mmPFA 1/16′ tube: O.D. 1.6 mm, I.D. 0.8 mmPolyimide tube: O.D. 2.6 mm, I.D. 2.25 mm⁽¹¹⁾: Explanation of symbols in air bubble occurrence and air bubblepercentage:◯: indicates that air bubble occurrence could not seenΔ: indicates that air bubble occurrence was seen slightlyX: indicates that air bubble occurrence was seen in large quantities⁽¹²⁾: Air bubble percentage was obtained by measuring length of airbubbles formed from LMFC to observation position for a fixed time andlength of liquid and by dividing the length of air bubbles by the totallength.

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) CH₃COOC₄H₉ 116.16 376 0.882 12510 425 170 (11) O₄H₈O 72.11 441 0.889 66 130 230 276 (27)-1 (12) C₂H₅OH46.07 841 0.794 78 44 425 386 (13) C₃H₇OC₃H₇ 102.18 285 0.725 69 131 405159 (14) C₆H₁₄ 86.18 335 0.659 69 120 240 171 (27)-2 (15) C₄H₉OC₄H₉130.23 0.764 142 4.8 185 131 (16) C₇H₈ 92.14 360 0.865 110.6 22 480 210(17) C₃H₇OH 60.1 63 0.787 82.5 32 399 293 (18) C₈H₁₈ 114.23 0.7 125 11210 137 (28)-2 (19) C₁₀H₂₂ 142.29 0.73 174 0.8 205 115 (28)-1 (20)C₁₂H₂₆ 170.34 0.75 216 0 200 99 (28) (21) C₄H₁₀O₂ 90.12 0.868 85 0 200216 (28) (22) C₆H₁₄O₂ 118.18 0.841 120 0 208 159 (28) (23) 222.28 1.01275 0 200 102 (28) (24) 102.13 0.873 88 0 460 191 (25) 98.15 0.95 156 0430 217 (26) C₁H₂₀O₂ 184.28 0.9 191 109 (28)^((1).)Name of solvent^((2).)Molecular formula^((3).)Molecular weight^((4).)Heat of vaporization (KJ/Kg)^((5).)Specific gravity^((6).)Boiling point (CC)^((7).)Vapor pressure (Torr/20° C.)^((8).)Ignition point^((9).)Gas volume (cc/ml)^((10).)Butyl acetate^((11).)THE^((12).)Ethanol^((13).)Di-isopropyl ether^((14).)Hexane^((15).)Dibutyl ether^((16).)Toluene^((17).)Isopropyl alcohol^((18).)Octane^((19).)Decane^((20).)Dociecane^((21).)Dimethoxyethane^((22).)Diethoxyethane^((23).)Tetraglime^((24).)Isopropyl acetate^((25).)Cyclohexane^((26).)Dipivaloylmethane^((27).)Result^((28).)Candidate

EXAMPLE 12

Regarding Restraint of Air Bubbles in Depressurized Vaporizer:

FIG. 28 shows an air bubble evaluating vaporizer.

The configuration is such that Sr/Ta raw material and Bi raw materialare mixed with each other in front of an evaporation head, and a sourceflows in one flow path of the two flow paths in the head, and only acarrier gas flows in the other flow path.

Hexane with a flow rate of 0.09 ccm was caused to flow, and the carrierpressure and air bubble occurrence were evaluated.

The results are given in Table 4. As shown in Table 4, the carrierpressure was stable, and air bubbles did not occur. TABLE 4 Carrier flowCarrier rate (ccm) pressure Condition 1 Source side 200 600 Torr Ar only50 600 Condition 2 Source side 250 780 Ar only 100 780Note:Carrier pressure in Table is indicated value of Bourdon tube pressuregage.

EXAMPLE 13

Regarding Restraint of Air Bubbles in Depressurized Vaporizer:

An example of an SBT thin film deposition process is explained withreference to FIG. 21.

A valve 2 is opened, and a valve 1 is closed, by which a reactionchamber is evacuated to a high vacuum. After several minutes, a wafer istransferred from a load lock chamber to a reaction chamber.

At this time, in a vaporizer,

-   hexaethoxystrontiumtantalum (Sr[Ta(OC₂H₅)₆]₂ 0.1 mol solution    (solvent: hexane) 0.02 ml/min),-   tri-t-amyloxide bismuth (Bi(O-t-C₅H₁₁)₃ 0.2 mol solution (solvent:    hexane) 0.02 ml/min),-   first carrier Ar (=200 sccm (introduced through a gas introduction    port 4)), and-   first carrier O₂ (=10 sccm (introduced through a gas introduction    port 4))-   flow and are drawn to a vacuum pump through the valve 2 and an    automatic pressure regulating valve.

At this time, the pressure gage is controlled to 4 Torr by the automaticpressure regulating valve.

When the temperature becomes stable several minutes after the wafer hasbeen transferred, the valve 1 is opened, and the valve 2 is closed, bywhich the following gas is caused to flow into the reaction chamber tostart deposition.

-   Hexaethoxystrontiumtantalum Sr[Ta(OC₂H₅)₆]₂ 0.1 mol solution    (solvent: hexane) 0.02 ml/min-   Tri-t-amyloxide bismuth Bi(O-t-C₅H₁₁)₃ 0.2 mol solution (solvent:    hexane) 0.02 ml/min-   First carrier Ar=200 sccm (introduced through the gas introduction    port 4)-   First carrier O₂=10 sccm (introduced through the gas introduction    port 4)-   Second carrier Ar=20 sccm (introduced through the gas introduction    port 200)-   O₂=10 sccm (introduced through the gas introduction port 200)-   Reaction oxygen O₂=200 sccm (introduced from the dispersion blowoff    portion lower portion 25)-   Reaction oxygen temperature 216° C. (temperature is controlled by    the heater provided separately before reaction oxygen is introduced    from the dispersion blowoff portion lower portion)-   Wafer temperature 475° C.

The reaction pressure chamber pressure is controlled to 1 Torr (by a notdescribed automatic pressure regulating valve).

Although air bubbles were not observed before the formation of film, airbubbles began to appear after three hours from the start of filmformation. Also, the pressure of carrier gas at the start time was 600Torr, but only the pressure of carrier gas in a line through which asource is supplied varied in the range of 720 to 780 Torr. Also, airbubbles occurred at any time in both Sr/Ta and Bi systems. The airbubbles exhibit behavior of repeated advance, retreat, and stagnation(FIG. 29).

EXAMPLE 14

Regarding Restraint of Air Bubbles in Depressurized Vaporizer:

An example of an SBT thin film deposition process is explained withreference to FIG. 21.

In this example, the pressure of CVD solution was increased from theconventional 3 atm. to 4 atm. (gage pressure).

A valve 2 is opened, and a valve 1 is closed, by which a reactionchamber is evacuated to a high vacuum. After several minutes, a wafer istransferred from a load lock chamber to a reaction chamber.

At this time, in a vaporizer,

-   hexaethoxystrontiumtantalum (Sr[Ta(OC₂H₅)₆]₂ 0.02 mol solution    (solvent: hexane) 0.10 ml/min),-   tri-t-amyloxide bismuth (Bi(O-t-C₅H₁₁)₃ 0.04 mol solution (solvent:    hexane) 0.10 ml/min),-   first carrier Ar (=200 sccm (introduced through a gas introduction    port 4)), and-   first carrier O₂ (=10 sccm (introduced through a gas introduction    port 4))-   flow and are drawn to a vacuum pump through the valve 2 and an    automatic pressure regulating valve.

At this time, the pressure gage is controlled to 4 Torr by the automaticpressure regulating valve.

When the temperature becomes stable several minutes after the wafer hasbeen transferred, the valve 1 is opened, and the valve 2 is closed, bywhich the following gas is caused to flow into the reaction chamber tostart deposition.

-   Hexaethoxystrontiumtantalum Sr[Ta(OC₂H₅)₆]₂ 0.02 mol solution    (solvent: hexane) 0.10 ml/min-   Tri-t-amyloxide bismuth Bi(O-t-C₅H₁₁)₃ 0.04 mol solution (solvent:    hexane) 0.10 ml/min-   First carrier Ar=200 sccm (introduced through the gas introduction    port 4)-   First carrier O₂=10 sccm (introduced through the gas introduction    port 4)-   Second carrier Ar=20 sccm (introduced through the gas introduction    port 200)-   O₂=10 sccm (introduced through the gas introduction port 200)-   Reaction oxygen O₂=200 sccm (introduced from the dispersion blowoff    portion lower portion 25)-   Reaction oxygen temperature 216° C. (temperature is controlled by    the heater provided separately before reaction oxygen is introduced    from the dispersion blowoff portion lower portion)-   Wafer temperature 475° C.

The reaction pressure chamber pressure is controlled to 1 Torr (by a notdescribed automatic pressure regulating valve).

Before the start of film formation, air bubble were not observed. Evenafter 10 hours has elapsed from the start of film formation, air bubblesdid not appear.

In example 13, it was considered that the carrier gas was caused to flowbackward in a solution line by fluctuations in the pressure of carriergas caused by the occurring air bubbles. Therefore, the pressure ofsolution was increased, and hence the flow rate thereof was increased,by which this problem could be solved.

FIG. 30 shows various types of vaporizers applicable to the presentinvention.

INDUSTRIAL APPLICABILITY

According to the present invention, there is provided a vaporizer usedfor a film forming apparatus such as a MOCVD film forming apparatus,which can be used for a long period of time without being clogged, andcan supply raw materials stably to a reaction section.

In this vaporizer, the occurrence of air bubbles can be restrained, andalso variations in thin film deposition speed caused by the air bubblescan be expected to be restrained.

1. A vaporizer comprising: (1) a dispersion section having a gas passageformed in the interior, a gas introduction port for introducing acarrier gas into said gas passage, means for supplying a raw materialsolution to said gas passage, a gas outlet for sending the carrier gascontaining the raw material solution to a vaporization section, andmeans for cooling said gas passage; and (2) the vaporization section forheating and vaporizing the carrier gas containing the atomized rawmaterial solution, which is sent from said dispersion section, having avaporization tube one end of which is connected to a reaction section offilm forming apparatus or other various types of apparatuses and theother end of which is connected to said gas outlet, and heating meansfor heating said vaporization tube, characterized in that the pressureof the reaction section is set lower than the pressure of saidvaporization tube.
 2. The vaporizer according to claim 1, characterizedin that the film forming apparatus is a normal-pressure CVD apparatus inwhich the pressure of the reaction section is controlled to 900 to 760Torr.
 3. The vaporizer according to claim 1, characterized in that thefilm forming apparatus is a depressurized CVD apparatus in which thepressure of the reaction section is controlled to 20 to 0.1 Torr.
 4. Thevaporizer according to claim 1, characterized in that the film formingapparatus is a low-pressure CVD apparatus in which the pressure of thereaction section is controlled to 0.1 to 0.001 Torr.
 5. A vaporizercomprising: (1) a dispersion section having a gas passage formed in theinterior, a gas introduction port for introducing a carrier gas intosaid gas passage, means for supplying a raw material solution to saidgas passage, a gas outlet for sending the carrier gas containing the rawmaterial solution to a vaporization section, and means for cooling saidgas passage; and (2) the vaporization section for heating and vaporizingthe carrier gas containing the raw material solution, which is sent fromsaid dispersion section, having a vaporization tube one end of which isconnected to a reaction section of film forming apparatus or othervarious types of apparatuses and the other end of which is connected tosaid gas outlet, and heating means for heating said vaporization tube,characterized in that (3) said dispersion section has a dispersionsection body having a cylindrical or conical hollow portion and a rodhaving an outside diameter smaller than the inside diameter of saidcylindrical or conical hollow portion, said rod has one or two or morespiral grooves on the vaporizer side at the outer periphery of said rod,and is inserted in said cylindrical or conical hollow portion, theinside diameter thereof sometimes spreading in a taper shape toward thevaporizer side, and the pressure of the reaction section is set lowerthan the pressure of said vaporization tube.
 6. The vaporizer accordingto claim 5, characterized in that the film forming apparatus is anormal-pressure CVD apparatus in which the pressure of the reactionsection is controlled to 900 to 760 Torr.
 7. The vaporizer according toclaim 5, characterized in that the film forming apparatus is adepressurized CVD apparatus in which the pressure of the reactionsection is controlled to 20 to 0.1 Torr.
 8. The vaporizer according toclaim 5, characterized in that the film forming apparatus is alow-pressure CVD apparatus in which the pressure of the reaction sectionis controlled to 0.1 to 0.001 Torr.
 9. A vaporizer comprising: (1) adispersion section having a gas passage formed in the interior, a gasintroduction port for introducing a carrier gas into said gas passage,means for supplying a raw material solution to said gas passage, a gasoutlet for sending the carrier gas containing the raw material solutionto a vaporization section, and means for cooling said gas passage; and(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from said dispersionsection, having a vaporization tube one end of which is connected to areaction section of film forming apparatus or other various types ofapparatuses and the other end of which is connected to said gas outlet,and heating means for heating said vaporization tube, characterized inthat an oxidizing gas can be added to the carrier gas from said gasintroduction port or an oxidizing gas can be introduced from a primaryoxygen supply port, and the pressure of the reaction section is setlower than the pressure of said vaporization tube.
 10. The vaporizeraccording to claim 9, characterized in that the film forming apparatusis a normal-pressure CVD apparatus in which the pressure of the reactionsection is controlled to 900 to 760 Torr.
 11. The vaporizer according toclaim 9, characterized in that the film forming apparatus is adepressurized CVD apparatus in which the pressure of the reactionsection is controlled to 20 to 0.1 Torr.
 12. The vaporizer according toclaim 9, characterized in that the film forming apparatus is alow-pressure CVD apparatus in which the pressure of the reaction sectionis controlled to 0.1 to 0.001 Torr.
 13. A vaporizer comprising: (1) adispersion section having a gas passage formed in the interior, a gasintroduction port for introducing a carrier gas into said gas passage,means for supplying a raw material solution to said gas passage, a gasoutlet for sending the carrier gas containing the raw material solutionto a vaporization section, and means for cooling said gas passage; and(2) the vaporization section for heating and vaporizing the carrier gascontaining the raw material solution, which is sent from said dispersionsection, having a vaporization tube one end of which is connected to areaction section of film forming apparatus or other various types ofapparatuses and the other end of which is connected to said gas outlet,and heating means for heating said vaporization tube, characterized inthat a radiation preventive portion having a minute hole is provided onthe outside of said gas outlet, the carrier gas and an oxidizing gas canbe introduced from said gas introduction port, and the pressure of thereaction section is set lower than the pressure of said vaporizationtube.
 14. The vaporizer according to claim 13, characterized in that thefilm forming apparatus is a normal-pressure CVD apparatus in which thepressure of the reaction section is controlled to 900 to 760 Torr. 15.The vaporizer according to claim 13, characterized in that the filmforming apparatus is a depressurized CVD apparatus in which the pressureof the reaction section is controlled to 20 to 0.1 Torr.
 16. Thevaporizer according to claim 13, characterized in that the film formingapparatus is a low-pressure CVD apparatus in which the pressure of thereaction section is controlled to 0.1 to 0.001 Torr.
 17. A vaporizercomprising: a disperser formed with a plurality of solution passages forsupplying a plurality of raw material solutions, a mixing section formixing said raw material solutions supplied from said solution passages,a supply passage one end of which communicates with said mixing sectionand which has an outlet on the vaporization section side, a gas passagearranged so that a carrier gas or a mixed gas of the carrier gas andoxygen is blown to the mixed raw material solution coming from saidmixing section in the supply passage, and cooling means for cooling saidsupply passage; and a vaporization section for heating and vaporizingthe carrier gas containing the raw material solutions, which is sentfrom said disperser, having a vaporization tube one end of which isconnected to a reaction section of a film forming apparatus or othervarious types of apparatuses and the other end of which is connected tothe outlet of said disperser, and heating means for heating saidvaporization tube, characterized in that a radiation preventive portionhaving a minute hole is provided on the outside of said outlet, aprimary oxygen supply port capable of introducing an oxidizing gas isprovided just near said dispersion blowoff portion, and the pressure ofthe reaction section is set lower than the pressure of said vaporizationtube.
 18. The vaporizer according to claim 17, characterized in that thefilm forming apparatus is a normal-pressure CVD apparatus in which thepressure of the reaction section is controlled to 900 to 760 Torr. 19.The vaporizer according to claim 17, characterized in that the filmforming apparatus is a depressurized CVD apparatus in which the pressureof the reaction section is controlled to 20 to 0.1 Torr.
 20. Thevaporizer according to claim 17, characterized in that the film formingapparatus is a low-pressure CVD apparatus in which the pressure of thereaction section is controlled to 0.1 to 0.001 Torr.
 21. A film formingapparatus including the vaporizer as described in any one of claims 1 to20.
 22. A vaporizing method in which a raw material solution isintroduced into a gas passage, and a carrier gas is sprayed toward theintroduced raw material solution, by which said raw material solution issheared and atomized into raw material mist, and then, said raw materialmist is supplied to a vaporization section to be vaporized,characterized in that control is carried out so that the pressures ofsaid carrier gas and said introduced raw material solution are almostequal in a region in which said carrier gas comes into contact with saidintroduced raw material solution.
 23. A vaporizing method in which a rawmaterial solution is introduced into a gas passage, and a carrier gas issprayed toward the introduced raw material solution, by which said rawmaterial solution is sheared and atomized into raw material mist, andthen, said raw material mist is supplied to a vaporization section to bevaporized, characterized in that control is carried out so that thepressure of said carrier gas is lower than the pressure of saidintroduced raw material solution in a region in which said carrier gascomes into contact with said introduced raw material solution.
 24. Thevaporizing method according to claim 23, characterized in that controlis carried out so that the pressure of said carrier gas is lower thanthe pressure of said introduced raw material solution by 760 Torr at amaximum in a region in which said carrier gas comes into contact withsaid introduced raw material solution.
 25. The vaporizing methodaccording to claim 40, characterized in that control is carried out sothat the pressure of said carrier gas is lower than the pressure of saidintroduced raw material solution by 100 to 10 Torr at a maximum in aregion in which said carrier gas comes into contact with said introducedraw material solution.
 26. A vaporizing method in which a raw materialsolution is introduced into a gas passage, and a carrier gas is sprayedtoward the introduced raw material solution, by which said raw materialsolution is sheared and atomized into raw material mist, and then, saidraw material mist is supplied to a vaporization section to be vaporized,characterized in that control is carried out so that the pressures ofsaid carrier gas and said raw material solution are higher than thevapor pressure of said introduced raw material solution in a region inwhich said carrier gas comes into contact with said introduced rawmaterial solution.
 27. The vaporizing method according to claim 26, inwhich a raw material solution is introduced into a gas passage, and acarrier gas is sprayed toward the introduced raw material solution, bywhich said raw material solution is sheared and atomized into rawmaterial mist, and then, said raw material mist is supplied to avaporization section to be vaporized, characterized in that control iscarried out so that the pressures of said carrier gas and said rawmaterial solution are 1.5 times or more higher than the vapor pressureof said introduced raw material solution in a region in which saidcarrier gas comes into contact with said introduced raw materialsolution.
 28. The vaporizing method according to any one of claims 22 to27, characterized in that oxygen is contained in said carrier gas inadvance.
 29. A film characterized by being formed after vaporization isaccomplished by the vaporizing method as described in any one of claims22 to
 27. 30. An electronic device including the film as described inclaim
 29. 31. A CVD thin film forming method characterized in that aftera pressurizing gas dissolved in a transfer solution using thepressurizing gas has been removed, the flow rate is controlled, and thevaporizer is connected to a CVD apparatus to form a thin film.
 32. TheCVD thin film deposition forming method according to claim 31,characterized in that the transfer solution using said pressurizing gasis caused to flow in a fluororesin pipe in which transmission speed iscontrolled, whereby only said pressurizing gas is removed.
 33. The CVDthin film deposition forming method according to claim 31 or 32,characterized in that when only said pressurizing gas is removed bycausing the transfer solution using said pressurizing gas to flow in afluororesin pipe etc. in which transmission speed is controlled, theremoval of said pressuring gas is accelerated by controlling theexternal environment of said fluororesin pipe etc.
 34. A vaporizingmethod in which a raw material solution is introduced into a passage andintroduced into a depressurized and heated vaporizer, and is sprayed ordripped into said vaporizer, whereby said raw material solution isatomized and vaporized, characterized in that control is carried out sothat the pressure of said raw material solution in the tip end portionof said passage is higher than the vapor pressure of the introduced rawmaterial solution.
 35. The vaporizing method according to claim 34,characterized in that control is carried out so that the pressure ofsaid raw material solution is 1.5 times or more the vapor pressure ofthe introduced raw material solution in the tip end portion of saidpassage.
 36. A vaporizing method in which a raw material solution and acarrier gas are introduced into a depressurized and heated vaporizer,and are sprayed into said vaporizer, whereby said raw material solutionis atomized and vaporized, characterized in that control is carried outso that the pressure of said raw material solution in the tip endportion of said passage is higher than the vapor pressure of theintroduced raw material solution.
 37. The vaporizing method according toclaim 36, characterized in that control is carried out so that thepressure of said raw material solution is 1.5 times or more the vaporpressure of said raw material solution in the tip end portion of saidpassage.
 38. The vaporizing method according to claim 35 or 37,characterized in that oxygen is contained in said carrier gas inadvance.
 39. The vaporizing method according to any one of claims 35 to37, characterized in that control is carried out so that the pressuresof said carrier gas and said introduced raw material solution are almostequal in a region in which said carrier gas comes into contact with saidintroduced raw material solution.
 40. The vaporizing method according toany one of claims 35 to 37, characterized in that control is carried outso that the pressure of said carrier gas is lower than the pressure ofsaid introduced raw material solution in a region in which said carriergas comes into contact with said introduced raw material solution. 41.The vaporizing method according to claim 40, characterized in thatcontrol is carried out so that the pressure of said carrier gas is lowerthan the pressure of said introduced raw material solution by 760 Torrat a maximum in a region in which said carrier gas comes into contactwith said introduced raw material solution.
 42. The vaporizing methodaccording to claim 41, characterized in that control is carried out sothat the pressure of said carrier gas is lower than the pressure of saidintroduced raw material solution by 100 to 10 Torr at a maximum in aregion in which said carrier gas comes into contact with said introducedraw material solution.
 43. The vaporizing method according to any one ofclaims 35 to 37, characterized in that control is carried out so thatthe pressures of said carrier gas and said raw material solution arehigher than the vapor pressure of said introduced raw material solutionin a region in which said carrier gas comes into contact with saidintroduced raw material solution.
 44. The vaporizing method according toclaim 43, characterized in that control is carried out so that thepressures of said carrier gas and said raw material solution are 1.5times or more higher than the vapor pressure of said introduced rawmaterial solution in a region in which said carrier gas comes intocontact with said introduced raw material solution.
 45. A CVD thin filmforming apparatus in which a transfer solution using a pressurizing gasis introduced into the vaporizer via a mass-flow controller, and thevaporizer is connected to the CVD apparatus, whereby a thin film isformed, characterized in that degassing means for removing a pressuringgas is provided on the upstream side of said mass-flow controller.